Facebook's share price surged 15% on Thursday. The company's market cap is now at $308.5 billion, just shy of Berkshire Hathaway's $310.2 billion.

Even as Zuckerberg climbed in the rankings, the global stock slide has hit the world's richest people particularly hard. The world's wealthiest seven people lost a combined $19 billion this month, according to Bloomberg.

Mark Zuckerberg is the sixth richest person in the world, even richer than the Koch Brothers, thanks to Facebook earnings.